Preparation of n,n-dimethylterephthalamic acid and terephthalamides from terephthalic acid and aliphatic amides or nitriles

ABSTRACT

Terephthalamide N-methyl derivatives are prepared by reacting terephthalic acid with lower alkyl cyanides or with lower alkanoic amides or N-methyl derivatives, in oleum solution, at atmospheric pressure, and at 25* C.- 100* C.

United States Patent Anthony T. Jurewicz Middlesex, NJ. 790,455

Jan. 10, 1969 Sept. 21,1971

Mobil Oil Corporation [72] Inventor [21 Appl. No. [22] Filed [45] Patented [73] Assignee [54] PREPARATION OF N,N-

DIMETI-lYLTEREPI-lTI-IALAMIC ACID AND TEREPIITI-IALAMIDES FROM TEREPI-ITIIALIC ACID AND ALIPHATIC AMIDES OR NITRILES 6 Claims, No Drawings 52 us. Cl 260/518 R,

260/558 A 5 l] Int. Cl C070 103/33 Primary Examiner-Henry R. Jiles Assistant ExaminerHarry l. Moatz Attorneys-Oswald G. Hayes, Andrew L. Gaboriault and Hastings S. Trigg ABSTRACT: Terephthalamide N-methyl derivatives are prepared by reacting terephthalic acid with lower alkyl cyanides or with lower alkanoic amides or N-methyl derivatives, in oleum solution, at atmospheric pressure, and at 25C.l00 C.

PREPARATION OF N,N-DIMETIIYLTEREPI-ITI-IALAMIC ACID AND TEREPI'ITI-IALAMIDES FROM TEREPHTI-IALIC ACID AND ALIPI-IATIC AMIDES OR NITRILES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the preparation of amides. It is more particularly concerned with the preparing of terephthalamides and N-methyl derivatives from terephthalic acid and fatty acid amides or nitriles.

2. Description of the Prior Art Terephthalamides have been prepared by reacting terephthaloyl chloride and an amine, or by reacting terephthalic acid and an amine. Both methods have disadvantages. The former requires the preparation of the acid chloride intermediate. The latter requires high pressure and temperatures, and the use of pressure equipment. It is a desideratum to prepare terephthalamides from readily available materials and without resort to pressure.

SUMMARY OF THE INVENTION This invention provides a process for preparing terephthalamides and N-methyl derivatives thereof that comprises reacting terephthalic acid with lower alkyl (C -C cyanides or with lower alkyl (c -C alkanoic acid amides or N-methyl derivatives, in oleum solution, at 25-l00 C.

DESCRIPTION OF SPECIFIC EMBODIMENTS One reactant in the process of this invention is terephthalic acid. This acid, usually prepared by catalytic oxidation of pxylene, is readily available commercially. I

The other reactants in the present process are lower (C -C cyanides and lower (C,-C alkanoic acid amides and their N-methyl derivatives. These compounds are readily prepared and most are commercially available. These reactants are methyl cyanide (acetonitrile); ethyl cyanide-(propionitrile); propyl cyanide (butyronitrile); formamide N-methylformamide; N,N-dimethylformamide; acetamide; N-methylacetamide; N,N-dimethylacetamide; propionamide; N-methylporpionamide; and N,N-dimethylpropionamide.

The process of this invention is carried out at atmospheric pressure and at temperatures between about 25 C. and about 100 C. Temperatures between about 75 C. and about 85 C.

are preferred. Reaction time can vary between about 1 hour and about hours. The solvent used in oleum having an S0,, content between about percent and about 8 percent, on a weight basis, i.e., 15 percent to 80 percent oleum. In general, the concentration of terephthalic acid in oleum can be between about 0.5 mole and about 7 moles per liter of oleum, depending upon the 80;, content; the higher content of SO dissolving more moles of terephthalic acid. The molar ratio of nitrile or amide to terephthalic acid is at least stoichiometric (2:1) up to about 4:1. Higher ratios can be used, but serve no useful purpose and unduly increase the amount of material to be handled.

EXAMPLE 1 Terephthalic acid (16.6 g., 0.1 mole) and N-methylacetamide (21.9 g., 0.3 mole) were charged to a 250 ml. round-bottom flask, along with 100 ml. of 30% S0 in H 80 The solution was heated at 80 C. for 300 minutes. The reaction mixture was cooled and poured onto 500 g. of ice. A precipitate was obtained. This was collected, washed with water, and dried. The yield of solid was 83% (16 g.). Analysis by infrared, NMR, and melting point (315-3l7) showed the structure to he N, N-dimethyl terephthalamlde.

EXAMPLE 2 Terephthalic acid (16.6 g. 0.1 mole) and acetamide (17.7 g., 0.3 mole) were charged to a 250 ml. round-bottom flask, along with 100 ml. of 30% 30;, in H 50 The solution was heated at C. for 360 minutes. The reaction mixture was cooled and poured onto 500g. of ice. A precipitate was obtained, which was collected, washed and dried. The yield was (16.0. g.). Analysis by infrared and NMR showed the structure to be terephthalamide.

EXAMPLE 3 Acetonitrile (12.3 g., 0.3 mole) was charged to a 250 ml. round-bottom flask containing terephthalic acid (16.6 g., 0.1 mole) in ml. of 30% SO, in H 80 at 20 C. After the addition was completed, the mixture was heated at 80 C. for 360 minutes. The reaction mixture was cooled and poured onto ice. A precipitate was obtained, which was collected, washed,

and dried. The yield was 90% (14.9 g.). Analysis by infrared and NMR showed the structure to be terephthalamide.

EXAMPLE 4 Terephthalic acid (16.6 g., 0.1 mole) and formamide (13.8 g., 0.3 mole) were charged to a 250 ml. round-bottom flask, along with 100 ml. of 30% 80;, in H 50 The mixture was heated at C. for 360 minutes. The reaction mixture was cooled and poured onto ice. The precipitate was collected, washed, and dried. A 69% yield to terephthalamide was obtained.

EXAMPLE 5 N-Methylformamide (21.9 g., 0.3 mole) and terephthalic acid (16.6 g., 0,1 mole) were charged to a 250 ml. round-bot? tom flask, along with 100 ml. of 30 S0 in H 50 The solution was heated at 80 C. for 360 minutes. The reaction mix- .ture was cooled and poured onto ice. The precipitate was collected, washed, and dried. The yield of N, N-dimethylterephthalamide was 83%.

EXAMPLE 6 EXAMPLE 7 N,N-Dimethylacetamide (26.4 g., 0.3 mole) and terephthalic acid (16.6 g., 0.1 mole) were charged to a 250 ml. roundbottom flask, along with 100 m1, of 30% SO, in H SQ The flask was heated to 110 C. for 400 minutes. The reaction was cooled and poured onto ice. Filtration, followed by extraction of the mother liquor with ether, and evaporation gave 36% yield of N,N-dimethylterephthalamic acid.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departingv from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifida-- tions are considered to be within the purview and scope of the appended claims.

I claim:

1. A process for preparing terephthalamide and N-methyl' derivatives thereof and N,N-dimethylterephthalamic acid that comprises reacting terephthalic acid with a reactant selected from the group consisting of lower alkyl (c -C acid amides, in 15 percent to 80 percent oleum solution, at 25-100 C., using between about 0.5 mole and about 7 moles terephthalic acid per liter of oleum and at least the stoichiometric amount of said reactant to terephthalic acid.

2. The process of claim I, wherein said reactant is N- methylacetamide.

3. The process of claim I, wherein said reactant is acetamide.

mide.

6. The process of claim 1, wherein said reactant is N- methylformamide.

23%;? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 7,9 Dated September 21, 1971 Inventor(s) Anthony T. Jurewicz It is certified that: error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 18, change "pressure" to --pressures-- Column 1, line 27, change "(c -C to "(c -c Column 1, line +0, after "formamide" should be Column 1, line +8, change "in" to --is-- Column 1, line 49, change "8" to --80-- Column 1, line 69, change "317-" to --317-- Column 2, line 67, change "(c -C to (C -C Signed and sealed this 25th da'y of April 1972.

(SEAL) Atheist:

EDWARD M.FLETCH 5F1,JR. ROBERT GOTISCHALK Attaching Officer Commissioner of Patents 

2. The process of claim 1, wherein said reactant is N-methylacetamide.
 3. The process of claim 1, wherein said reactant is acetamide.
 4. The process of claim 1, wherein said reactant is acetonitrile.
 5. The process of claim 1, wherein said reactant is formamide.
 6. The process of claim 1, wherein said reactant is N-methylformamide. 